Astronauts replace old batteries in 1st of 5 spacewalks

Astronauts hustled through the first of five spacewalks to replace old batteries at the International Space Station on Sunday. Christina Koch and Andrew Morgan removed three old batteries and installed two new ones delivered just a week ago, getting a jump on future work. These new lithium-ion batteries are so powerful that only one is needed for every two old ones.

Female 8-year-old bison dies in Golden Gate Park

It was a sad day at the Buffalo Paddock in San Francisco's Golden Gate Park on Friday. Brunhilda, the eight-year-old female American bison who lived there, suffered severe kidney disease, which contributed to her passing, according to preliminary necropsy results. 

Stanford improves HIV 'spit' test

Bay Area scientists say they have developed a needle-free way to test for HIV. Early experiments showed promising results for the spit test. Dr. Dave Seftel is the study co-author and explains these new findings.